1. Field of the Invention
The present invention relates to a material for a luminescent (organic luminescent) device capable of converting electric energy into light and emitting light and also relates to a luminescent device using the material. The luminescent device can be suitably used in the fields of display device, display, back light, electrophotography, illumination light source, recording light source, reading light source, marking, billboard, interior decoration and the like.
The present invention also relates to a tetraarylmethane compound useful as a charge transporting agent for use in organic electroluminescent (EL) devices and electrophotographic photoreceptors.
2. Description of the Related Art
At the present time, developments and studies on various display devices are being aggressively made. In particular, organic electroluminescent (EL) devices can obtain highly bright luminescence at a low voltage and accordingly, are drawing an attention as a promising display device.
VanSlyke, Tang et al. reveal, for example, in U.S. Pat. Nos. 4,539,507 and 4,720,432, and JP-A-5-234681 (the term xe2x80x9cJP-Axe2x80x9d as used herein means an xe2x80x9cunexamined published Japanese patent applicationxe2x80x9d) that when an aromatic tertiary amine containing a phenyl group, a phenylene group or a biphenylene group is used in the electron (hole) injecting and transporting zone of an internal connection organic electroluminescent (EL) device, the light output stability is improved and the operating life is prolonged. Thereafter, improvements of aromatic tertiary amine are studied by many researchers with an attempt to attain further stability of the light output, and reported in a large number of patent applications and scientific literatures. For example, biphenyl-base tertiary amines are reported in Japanese Journal of Applied Physics, 27, L269 (1988), JP-A-59-194393, Appl. Phys. Lett., 66, 2679 (1995), JP-A-5-234681, JP-A-7-331238, JP-A-8-48656 and WO95/09147, and star burst tertiary amines are reported in Appl. Phys. Lett., 65, 807 (1994), and JP-B-7-110940 (the term xe2x80x9cJP-Bxe2x80x9d as used herein means an xe2x80x9cexamined Japanese patent publicationxe2x80x9d). However, the compounds heretofore disclosed are not satisfied in the performance (particularly, storage stability) and still in need of improvements.
Among organic EL devices, devices obtained by laminating organic substance layer through vacuum evaporation make a success in realizing light emission with high luminance. However, in view of simplification of the production process, workability and the like or for obtaining a large area, the device is preferably fabricated by a coating method. The devices fabricated by the conventional coating method are, however, inferior in the luminance of light emitted and the luminescent (quantum) efficiency as compared with the devices fabricated by the deposition method. Thus, improvements are still in need for attaining light emission with high luminance and high efficiency.
In recent years, the practical use of electrophotographic photoreceptor (organic photoconductor (OPC)) has been spreading rapidly, and the OPC completely plays a central role of electrophotographic photoreceptors. Most of recent OPCs are laminate type OPCs comprising a charge generating material (CGM) and a charge transfer material (CTM). Due to electrophotographic photoreceptors of laminate type OPC, sensitivity to visual light, charge retaining properties, surface strength, etc., are greatly improved. While hydrazone compounds (JP-B-55-42380, JP-A-57-101844, JP-A-54-150128, etc.), triarylamine compounds (JP-B-58-32372, etc.) and stilbene compounds (JP-A-58-198043, etc.) are used as CTM, the devices using these CTM compounds in the related art are inferior in properties (e.g., sensitivity) for recent speeding up. Accordingly, improvements are still in need. The study on CTM has been extensively carried out, and novel hydrazone compounds (JP-A-8-143550), carbazole type stilbene compounds (JP-A-8-59615) and tri-substituted ethylene compounds (JP-A-63-225660, JP-A-9-59256) are proposed recently. However, improvements are still in need.
An object of the present invention is to provide a material for an organic luminescent device capable of driving at low voltage, emitting light with high luminance and high efficiency, and exhibiting excellent stability on repeated use, and to provide an organic luminescent device using the material.
Another object of the present invention is to provide i a novel compound for use in organic electroluminescent (EL) and electrophotoraphic photoreceptors.
A further object of the present invention is to provide a novel charge transporting agent for use in organic electroluminescent (EL) devices and electrophotoraphic photoreceptors, which can exhibit excellent charge transporting ability or storage stability.
The above-described objects can be attained by the following means:
(1) an organic luminescent device material which is a compound represented by the following formula (I):
Formula (I) 
wherein V, W, X and Y each represents L1xe2x80x94NR1R2, wherein R1 and R2 each represents an aliphatic hydrocarbon group, an aryl group or a heterocyclic group, R1 and R2 may be combined directly or indirectly to form a ring, and L1 represents a divalent linking group containing an aryl group and/or an aromatic heterocyclic group;
(2) an organic luminescent device material which is a compound represented by the following formula (II):
Formula (II) 
wherein Ar21 and Ar22 each represents an aryl group, Ar21 and Ar22 may be combined to each other directly or indirectly to form a ring, and L2 represents a divalent linking group containing an aryl group and/or an aromatic heterocyclic group;
(3) an organic luminescent device material which is a compound represented by the following formula (III):
Formula (III) 
wherein Ar31 and Ar32 each represents an aryl group, Ar31 and Ar32 may be combined to each other directly or indirectly to form a ring, and L3 represents an arylene group;
(4) an organic luminescent device material which is a compound represented by the following formula (IV):
Formula (IV) 
wherein Ar41 and Ar42 each represents an aryl group, Ar41 and Ar42 may be combined to each other directly or indirectly to form a ring, n represents an integer of from 1 to 4, R represents a substituent, and m represents an integer of from 0 to 4;
(5) an organic luminescent device comprising a pair of electrodes having formed therebetween a light emitting layer or a plurality of organic compound thin films including a light emitting layer, wherein at least one layer contains the organic luminescent device material described in (1) to (4) above;
(6) an organic luminescent device comprising a pair of electrodes having formed therebetween a light emitting layer or a plurality of organic compound thin films including a light emitting layer, wherein at least one layer comprises a polymer having dispersed therein the organic luminescent device material described in (1) to (4) above; and
(7) a novel tetraarylmethane compound represented by the following formula (V):
Formula (V) 
wherein Ar1 and Ar2, which may be the same or different, each represents an aryl group which may be substituted, Ar1 and Ar2 may be combined directly or indirectly through a linking group, R represents a halogen atom, an alkyl group which may be substituted, an aryl group which may be substituted, an alkoxy group which may be substituted, an aryloxy group which may be substituted, a dialkylamino group which may be substituted, an N-alkyl-N-arylamino group which may be substituted or a diarylamino group which may be substituted, when a plurality of Rs are present, Rs may be the same or different, m represents an integer of from 0 to 4, and n represents an integer of from 1 to 4.
The compound represented by formula (I) is described in detail below.
V, W, X and Y, which may be the same or different, each represents L1xe2x80x94NR1R2, wherein R1 and R2 each represents an aliphatic hydrocarbon group, an aryl group or a heterocyclic group, R1 and R2 may be combined directly or indirectly to form a ring, and L1 represents a divalent linking group containing an aryl group and/or an aromatic heterocyclic group.
The aliphatic hydrocarbon group represented by R1 or R2 may be a linear, branched or cyclic hydrocarbon group and the hydrocarbon group is preferably an alkyl group (preferably having from 1 to 30 carbon atoms, more preferably from 1 to 20 carbon atoms, still more preferably from 1 to 12 carbon atoms, e.g., methyl, ethyl, iso-propyl, tert-butyl, n-octyl, n-decyl, n-hexadecyl, cyclopropyl, cyclopentyl, cyclohexyl), an alkenyl group (preferably having from 2 to 30 carbon atoms, more preferably from 2 to 20 carbon atoms, still more preferably from 2 to 12 carbon atoms, e.g., vinyl, allyl, 2-butenyl, 3-pentenyl) or an alkynyl group (preferably having from 2 to 30 carbon atoms, more preferably from 2 to 20 carbon atoms, still more preferably from 2 to 12 carbon atoms, e.g., propargyl, 3-pentynyl), more preferably an alkyl group or an alkenyl group, and still more preferably an alkyl group.
The aryl group represented by R1 or R2 is a monocyclic or condensed ring aryl group preferably having from 6 to 30 carbon atoms, more preferably from 6 to 20 carbon atoms, still more preferably from 6 to 12 carbon atoms, and examples thereof include phenyl, naphthyl, anthracenyl, phenanthrenyl and vinylene. Among these, preferred are phenyl and naphthyl.
The heterocyclic group represented by R1 or R2 is a monocyclic or condensed ring heterocyclic group (preferably having from 1 to 20 carbon atoms, more preferably from 1 to 12 carbon atoms, still more preferably from 2 to 10 carbon atoms), preferably an aromatic heterocyclic group containing at least one of nitrogen atom, oxygen atom, sulfur atom and selenium atom. Specific examples of the heterocyclic group represented by R1 or R2 include pyrrolidine, piperidine, pyrrole, furan, thiophene, imidazoline, imidazole, benzimidazole, naphthoimidazole, thiazolidine, thiazole, benzothiazole, naphthothiazole, isothiazole, oxazoline, oxazole, benzoxazole, naphthoxazole, isoxazole, selenazole, benzoselenazole, naphthoselenazole, pyridine, quinoline, isoquinoline, indole, indolenine, pyrazole, pyrazine, pyrimidine, pyridazine, tirazine, indazole, purine, phthalazine, naphtylidine, quinoxaline, quinazoline, cinnoline, pteridine, phenanthroline, tetrazaindene, oxadiazole, thiadiazole, triazole and tetrazole. Among these, pyrrole, thiophene, pyridine and quinoline are preferred, and thiophene, pyridine and quinoline are more preferred.
The aliphatic hydrocarbon group, the aryl group and the heterocyclic group represented by R1 or R2 each may have a substituent. Examples of the substituent include an alkyl group (preferably having from 1 to 20 carbon atoms, more preferably from 1 to 12 carbon atoms, still more preferably from 1 to 8 carbon atoms, e.g., methyl, ethyl, iso-propyl, tert-butyl, n-octyl, n-decyl, n-hexadecyl, cyclopropyl, cyclopentyl, cyclohexyl), an alkenyl group (preferably having from 2 to 20 carbon atoms, more preferably from 2 to 12 carbon atoms, still more preferably from 2 to 8 carbon atoms, e.g., vinyl, allyl, 2-butenyl, 3-pentenyl), an alkyl group (preferably having from 2 to 20 carbon atoms, more preferably from 2 to 12 carbon atoms, still more preferably from 2 to 8 carbon atoms, e.g., propargyl, 3-pentynyl), an aryl group (preferably having from 6 to 40 carbon atoms, more preferably from 6 to 30 carbon atoms, still more preferably from 6 to 20 carbon atoms, e.g., phenyl, p-methylphenyl, naphthyl), an amino group (preferably having from 0 to 50 carbon atoms, more preferably from 2 to 48 carbon atoms, still more preferably from 2 to 28 carbon atoms, e.g., amino, methylamino, dimethylamino, diethylamino, dibenzylamino), an alkoxy group (preferably having from 1 to 20 carbon atoms, more preferably from 1 to 12 carbon atoms, still more preferably from 1 to 8 carbon atoms, e.g., methoxy, ethoxy, butoxy), an aryloxy group (preferably having from 6 to 30 carbon atoms, more preferably from 6 to 20 carbon atoms, still more preferably from 6 to 18 carbon atoms, e.g., phenyloxy, 2-naphthyloxy), an acyl group (preferably having from 1 to 20 carbon atoms, more preferably from 1 to 16 carbon atoms, still more preferably from 1 to 12 carbon atoms, e.g., acetyl, benzoyl, formyl, pivaloyl), an alkoxycarbonyl group (preferably having from 2 to 20 carbon atoms, more preferably from 2 to 16 carbon atoms, still more preferably from 2 to 12 carbon atoms, e.g., methoxycarbonyl, ethoxycarbonyl), an aryloxycarbonyl group (preferably having from 7 to 20 carbon atoms, more preferably from 7 to 16 carbon atoms, still more preferably from 7 to 10 carbon atoms, e.g., phenyloxycarbonyl), an acyloxy group (preferably having from 2 to 20 carbon atoms, more preferably from 2 to 16 carbon atoms, still more preferably from 2 to 10 carbon atoms, e.g., acetoxy, benzoyloxy), an acylamino group (preferably having from 2 to 20 carbon atoms, more preferably from 2 to 16 carbon atoms, still more preferably from 2 to 10 carbon atoms, e.g., acetylamino, benzoylamino), an alkoxycarbonylamino group (preferably having from 2 to 20 carbon atoms, more preferably from 2 to 16 carbon atoms, still more preferably from 2 to 12 carbon atoms, e.g., methoxycarbonylamino), an aryloxycarbonylamino group (preferably having from 7 to 20 carbon atoms, more preferably from 7 to 16 carbon atoms, still more preferably from 7 to 12 carbon atoms, e.g., phenyloxy, carbonylamino), a sulfonamino group (preferably having from 1 to 20 carbon atoms, more preferably from 1 to 16 carbon atoms, still more preferably from 1 to 12 carbon atoms, e.g., methanesulfonylamino, benzenesulfonylamino), a sulfamoyl group (preferably having from 0 to 20 carbon atoms, more preferably from 0 to 16 carbon atoms, still more preferably from 0 to 12 carbon atoms, e.g., sulfamoyl, methylsulfamoyl, dimethylsulfamoyl, phenylsulfamoyl), a sulfamoylamino group (preferably having from 0 to 20 carbon atoms, more preferably from 1 to 16 carbon atoms, still more preferably from 1 to 12 carbon atoms, e.g., sulfamoylamino, 3-methylsulfamoylamino), a carbamoyl group (preferably having from 1 to 20 carbon atoms, more preferably from 1 to 16 carbon atoms, still more preferably from 1 to 12 carbon atoms, e.g., carbamoyl, methylcarbamoyl, diethylcarbamoyl, phenylcarbamoyl), an alkylthio group (preferably having from 1 to 20 carbon atoms, more preferably from 1 to 16 carbon atoms, still more preferably from 1 to 12 carbon atoms, e.g., methylthio, ethylthio), an arylthio group (preferably having from 6 to 20 carbon atoms, more preferably from 6 to 16 carbon atoms, still more preferably from 6 to 12 carbon atoms, e.g., phenylthio), a sulfonyl group (preferably having from 1 to 20 carbon atoms, more preferably from 1 to 16 carbon atoms, still more preferably from 1 to 12 carbon atoms, e.g., mesyl, tosyl), a sulfinyl group (preferably having from 1 to 20 carbon atoms, more preferably from 1 to 16 carbon atoms, still more preferably from 1 to 12 carbon atoms, e.g., methanesulfinyl, benzenesulfinyl), a ureido group (e.g., preferably having from 1 to 20 carbon atoms, more preferably from 1 to 16 carbon atoms, still more preferably from 1 to 12 carbon atoms, e.g., ureido, methylureido, phenylureido), a phosphoric acid amide group (preferably having from 1 to 20 carbon atoms, more preferably from 1 to 16 carbon atoms, still more preferably from 1 to 12 carbon atoms, e.g., diethylphosphoric acid amide, phenylphosphoric acid amide), a hydroxy group, a mercapto group, a halogen atom (e.g., fluorine, chlorine, bromine, iodine), a cyano group, a sulfo group, a carboxyl group, a nitro group, a hydroxamic acid group, a sulfino group, a hydrazino group, an imino group and a heterocyclic group (preferably having from 1 to 20, more preferably from 1 to 12 carbon atoms; examples of the hetero atom include nitrogen atom, oxygen atom, sulfur atom, and specific examples thereof include imidazolyl, pyridyl, quinolyl, furyl, piperidyl, morpholino, benzoxazolyl, benzimidazolyl and banzothiazolyl). These substituents each may be further substituted. When two or more substituents are present, they may be the same or different. Furthermore, if possible, the substituents may be combined to form a ring.
The substituent is preferably an alkyl group, an alkenyl group, an aralkyl group, an aryl group, an alkoxy group, an aryloxy group, an amino group, a halogen atom or a heterocyclic group, more preferably. an alkyl group, an alkenyl group, an aryl group, an alkoxy group, an aryloxy group, an amino group, a halogen atom or an aromatic heterocyclic group, still more preferably an alkyl group, an aryl group, an alkoxy group, an aryloxy group, an amino group or a halogen atom, particularly preferably an alkyl group having from 1 to 6 carbon atoms (e.g., methyl, tert-butyl, cyclohexyl), an aryl group having from 6 to 20 carbon atoms (e.g., phenyl, naphthyl, biphenyl), an alkoxy group having from 1 to 8 carbon atoms (e.g., methoxy, ethoxy, cyclohexyloxy), an aryloxy group having from 6 to 18 carbon atoms (e.g., phenoxy, naphthoxy), a dialkylamino group having from 2 to 8 carbon atoms (e.g., dimethylamino, diethylamino), an N-alkyl-N-arylamino group having from 7 to 15 carbon atoms (e.g., N-methyl-N-phenylamino, N-methyl-N-methylamino), a diarylamino group having from 12 to 28 carbon atoms (e.g., diphenylamino, N-(3-methylphenyl)-N-phenylamino, N-(1-naphthyl)-N-phenylamino) or a chlorine atom.
In the case where R1 and R2 are not combined directly or indirectly to form a ring, R1 and R2 each is preferably a substituted or unsubstituted phenyl group or a naphthyl group, more preferably a substituted or alkyl-substituted phenyl group or a naphthyl group.
In the case where R1 and R2 are combined directly or indirectly to form a ring, the number of ring member is from 5 to 7. In the case where R1 and R2 are combined indirectly, namely when a 6-membered or greater membered ring is formed, examples of the linking group include the following divalent groups. 
Rxe2x80x2 represents an alkyl or aryl group. The alkyl or aryl group may have a substituent and examples of the substituent include those described above as the substituent which R1 or R2 may have.
The divalent linking group represented by L1 contains at least one aryl group or aromatic heterocyclic group and examples thereof include an arylene group, a divalent aromatic heterocyclic group and a combination of an arylene group or a divalent aromatic heterocyclic group with an alkylene group, an alkenylene group, xe2x80x94Oxe2x80x94, xe2x80x94Sxe2x80x94, xe2x80x94SO02xe2x80x94, xe2x80x94COxe2x80x94 or xe2x80x94N(Ra)xe2x80x94 (wherein Ra represents a hydrogen atom, an aliphatic hydrocarbon group, an aryl group or a heterocyclic group).
The divalent linking group represented by L1 is preferably an arylene group, a divalent aromatic heterocyclic group or a combination of an arylene group or a divalent aromatic heterocyclic group with xe2x80x94N(Ra)xe2x80x94. Examples thereof include the following divalent linking groups. 
The divalent linking group represented by L1 is more preferably an arylene group, still more preferably phenylene biphenylene, triphenylene or tetraphenylene, particularly preferably phenylene or biphenylene.
The divalent linking group represented by L1 may have a substituent and examples of the substituent include those described above as the substituent of R1 and R2. The substituent of L1 is preferably a halogen atom (e.g., fluorine, chlorine, bromine or iodine, preferably fluorine or chlorine, more preferably chlorine), an alkyl group (preferably having from 1 to 20 carbon atoms, e.g., methyl, ethyl, isopropyl, n-butyl, t-butyl, n-dodecyl, cyclohexyl), an aryl group (preferably having from 6 to 36 carbon atoms, e.g., phenyl, naphthyl, anthracenyl, phenanthrenyl, pyrenyl, naphthacenyl, pentacenyl, pentaphenyl), an alkoxy group (preferably having from 1 to 20 carbon atoms, e.g., methoxy, ethoxy, isopropoxy, n-hexyloxy, cyclohexyloxy, octyloxy, dodecyloxy), an aryloxy group (preferably having from 6 to 36 carbon atoms, e.g., phenoxy, naphthoxy, anthracenoxy, pentacenoxy), an amino group (preferably having from 2 to 20 carbon atoms), a dialkylamino group (e.g., N-ethyl-N-butylamino), an N-alkyl-N-arylamino group having from 7 to 42 carbon atoms (e.g., N-methyl-N-phenylamino, N-ethyl-N-phenylamino, N-isopropyl-N-(3-methylphenyl)amino, N-methyl-N-(1-naphthyl)amino, N-butyl-N-(1-naphthacenyl)amino) or a diarylamino group having from 12 to 48 carbon atoms (e.g., diphenylamino, N-phenyl-N-(1-naphthyl)amino, N-(1-naphthyl)-N-(1-naphthyl)amino, N-phenyl-N-(1-anthracenyl)-amino, N-(1-anthracenyl)-N-(1-phenanrenyl)amino).
The substituent of L1 may be further substituted and examples of the substituent include a halogen atom, an alkyl group, an aryl group, a heterocyclic group, a cyano group, a hydroxy group, a nitro group, a carboxy group, a sulfo group, an amino group, an alkoxy group, an aryloxy group, an acylamino group, an alkylamino group, an anilino group, a ureido group, a sulfamoylamino group, an alkylthio group, an arylthio group, an alkoxycarbonylamino group, a sulfonamido group, a carbamoyl group,. a sulfamoyl group, a sulfonyl group, an alkoxycarbonyl group, a heterocyclic oxy group, an azo group, an acyloxy group, a carbamoyloxy group, a silyloxy group, an aryloxycarbonylamino group, an imido group, a heterocyclic thio group, a sulfinyl group, a phosphonyl group, an aryloxycarbonyl group, an acyl group, a silyl group and an azolyl group. Among these, an alkyl group, an aryl group, an alkoxy group, a dialkylamino group and a diarylamino group are preferred, and an alkyl group and a diarylamino group are more preferred.
Among the compounds represented by formula (I), the compound represented by the following formula (II) is preferred.
Formula (II) 
In formula (II), Ar21 and Ar22 each represents an aryl group and Ar21 and Ar22 may be combined to each other directly or indirectly to form a ring. The aryl group represented by Ar21 or Ar22 has the same meaning as the aryl group represented by R1 or R2 in formula (I) and the preferred range thereof is also the same.
L2 represents a divalent linking group containing an aryl group and/or an aromatic heterocyclic group. The divalent linking group represented by L2 has the same meaning as L1 in formula (I) and the preferred range thereof is also the same.
Among the compounds represented by formula (I), the compound represented by the following formula (III) is more preferred.
Formula (II) 
In formula (II), Ar31 and Ar32 each represents an aryl group and Ar31 and Ar32 may be combined to each other directly or indirectly to form a ring. The aryl group represented by Ar31 or Ar32 has the same meaning as the aryl group represented by R1 or R2 in formula (I) and the preferred range thereof is also the same.
L3 represents an arylene group. The arylene group represented by L3 has the same meaning as the arylene group described with respect to the divalent linking group represented by L1 in formula (I) and the preferred range thereof is also the same.
Among the compounds represented by formula (I), the compound represented by the following formula (IV) is still more preferred.
Formula (IV) 
In formula (IV), Ar41 and Ar42 each represents an aryl group and Ar41 and Ar42 may be combined to each other directly or indirectly to form a ring. The aryl group represented by Ar41 or Ar42 has the same meaning as the aryl group represented by R1 or R2 in formula (I) and the preferred range thereof is also the same.
n represents an integer of from 1 to 4, preferably 1 or 2.
R represents a substituent. The substituent represented by R has the same meaning as the substituent of L1 in formula (I) and the preferred range thereof is also the same.
m represents an integer of from 0 to 4, preferably 0 or 1. When m is an integer of from 2 to 4, the substituents R may be the same or different.
The compound represented by formula (I) of the present invention may be a low molecular weight compound, a high molecular weight compound (preferably having a weight average molecular weight of from 1,000 to 5,000,000, more preferably from 5,000 to 2,000,000, still more preferably from 10,000 to 1,000,000) in which the residue is connected to the polymer main chain, or a high molecular weight compound (preferably having a weight average molecular weight of from 1,000 to 5,000,000, more preferably from 5,000 to 2,000,000, still more preferably from 10,000 to 1,000,000) containing the compound of the present invention in the main chain thereof. In the case of a high molecular weight compound, the compound may be a homopolymer or a copolymer with another monomer.
As a matter of convenience, formula (I) is shown by a limiting structural formula, but a tautomer thereof may also be used.